The present invention generally relates to the unloading of documents from a stack or stacks and the subsequent insertion of such documents into envelopes. More specifically, the present invention relates to an automated system that discharges a single document or several documents onto to a discharge conveyor and loads the documents into an open envelope while maintaining the required control over the documents to reduce mishandling.
Currently, many systems exist for the automated insertion of documents into envelopes and the subsequent processing of the envelopes for automated mailing. For envelope insertion operations, it is generally necessary to provide a stack of envelopes which have had the envelope flap opened so that the materials to be inserted may be inserted therein. In typical prior art systems, such as shown in U.S. Pat. Nos. 4,020,615; 4,888,938; and 5,247,780, opening fingers or blades are inserted into the envelope to allow documents or articles to be slid into the opened envelope.
An inherent drawback in envelope inserting systems that includes blades or fingers to open the envelopes is that at higher speeds, the blades or fingers that come into contact with the envelope will tear or otherwise damage the envelope, thereby resulting in system shutdowns and delays. Additionally, high speed operation requires the mechanical fingers to continuously operate, which results in wear and mechanical breakdowns.
Along with the inherent problems that result from the use of insertion fingers or blades is the lack of control over the product as it moves at high speeds throughout the system. A primary reason for the lack of control of articles being inserted into the envelopes is the continual starting and stopping of both the articles and the envelopes throughout the entire production process. Additionally, in many currently available machines and systems, both the documents and envelopes change directions several times during the insertion process. During each of the direction changes, the articles and envelopes suffer from a lack of control which tends to restrict the speed of the production process.
An additional problem with currently available systems running at higher speeds is the deterioration of the gears and cams that are used to operate the unloading devices and the devices used to insert the documents into envelopes. Therefore, a need currently exists for an improved system for the automated insertion of documents and other articles into envelopes that maintains the required control over the documents and envelopes to allow for the high speed stuffing of envelopes. Further, it is an object of the present invention to provide a system that maintains the required amount of control over the articles as the individual articles move in a single direction from accumulated stacks of documents to finally being placed within the desired envelope. Further, it is an object of the present invention to provide an outfeed conveyor assembly that allows multiple envelope insertion lines to be accumulated on a common conveyor system.
The present invention is a system for the high speed and automated insertion of documents into envelopes. The system operates to maintain control over the documents throughout the process and operates in a single, first direction such that the envelopes and documents do not change direction.
The envelope inserter of the present invention includes a document conveyor that extends in a first direction. The document conveyor terminates at a discharge end and includes an endless drive chain having a plurality of tabs. Each of the tabs are spaced along the length of the drive chain and function to engage and move the documents along the length of the document conveyor.
The envelope inserter further includes a plurality of individual document feeding devices spaced along the length of the document conveyor. Each of the document feeding devices includes a stacking bin that receives a stack of documents to be dispensed. The stack of documents contained within the stacking bin can be folded or flat documents, depending upon the type of material to be inserted into the envelopes.
Each of the document feeding devices includes a suction device positioned beneath the bottom end of the stacking bin and is operable to remove the lowermost document from the accumulated stack. The suction device includes a suction cup and support arm that are movable between a grasping position, a discharge position, and a retracted position. When the suction device is in the grasping position, a source of negative air pressure is applied to the lowermost document through a suction cup contained on the suction device. After the supply of negative air pressure is applied to the lowermost document, the suction device can be moved to the discharge position to pull the lowermost document out of the accumulated stack in the stacking bin.
As the suction device pulls the lowermost document from the accumulated stack, the document is pulled into contact with a discharge nip formed between a pair of rotating discharge belts. The discharge belts are operated at substantially the same speed such that when the document enters into the discharge nip and the supply of negative air pressure is removed, the pair of rotating discharge belts act to direct the document onto the document conveyor. One of the discharge belts passes around a drive member that is operable to adjust the position of the discharge nip. Specifically, the drive member operates to move the discharge nip upward to pull the document from the suction device when the suction device is in the discharge position. As the discharge belts engage the document, the suction device moves to the fully retracted position that is completely out of the way of the document as it is pulled from the stack. The operation of each document feeding device is controlled by a control unit that times the discharge of each document such that each document is positioned in contact with one of the moving tabs on the document conveyor.
As the discharged documents are moved along the document conveyor, the discharged documents pass beneath a document insertion device. The document insertion device is positioned near the discharge end of the document conveyor and operates to act upon the documents as the documents approach the discharge end of the document conveyor. The document insertion device includes a continuous belt that operates in-line with the document conveyor in the first direction.
The continuous belt of the document insertion device includes a plurality of pusher members that contact the individual documents supported along the document conveyor. Each of the pusher members contacts the document and pushes the document off of the discharge end of the document conveyor and onto a support platform. The endless belt of the document insertion device is operated at a speed slightly faster than the speed of the document conveyor such that the documents are accelerated by the pusher members of the document insertion device.
A stacking device that includes a stack of opened envelopes is positioned immediately adjacent to the discharge end of the document insertion device such that the pusher members of the document insertion device push the documents into the uppermost envelope of the opened envelope stack. A blast of air is directed into the uppermost envelope of the opened envelope stack to open the envelope prior to insertion of the document by the document insertion device.
The stack of opened envelopes in the stacking device is created by the combination of an envelope feeding device and an envelope conveyor. The envelope feeding device is generally identical to the plurality of document feeding devices and thus includes a stacking bin including a supply of unopened envelopes. The unopened envelopes contained within the stack in the storage bin are fed individually into a discharge nip by a suction device. As the unopened envelopes are fed from the stack, a powerful air blast is used to open the envelope flap prior to the envelope entering into the discharge nip.
The now opened envelopes are fed from the envelope feeding device to an envelope conveyor where a continuous string of opened envelopes are shingled. The shingled, opened envelopes are fed from the envelope conveyor to the bottom of the opened envelope stack contained within the stacking device. The stacking device includes a photoeye that communicates with a control unit such that the control unit can control the operation of both the envelope conveyor and the envelope feeding device to feed envelopes to the stacking device as the height of the opened envelope stack decreases.
After the uppermost envelope in the opened envelope stack is stuffed with a document by the document insertion device, the envelope is lifted off of the stack by a suction device. The envelope is fed by a transfer device to an outfeed conveyor. While on the outfeed conveyor, the envelope flap is wetted and pressed into a closed position. The outfeed conveyor extends in a second direction that is different from the first direction of the document conveyor. From the outfeed conveyor, the closed envelopes are fed to conventional processing equipment, such as mailing and sorting machines.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.